Glossary

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

A

Adaptation: A process of evolutionary (genetic) adjustment that fits populations to their environment.
Allele: An alternative form of a particular genetic locus; there may be one to several alleles of each gene in a population.
Asexual reproduction: Reproduction without fertilization, e.g. rooting of cuttings.

B

Breeding hall: A simplified greenhouse used to encourage plant material to flower in order to carry out controlled pollination work.
Breeding orchard: A collection of selected trees or species established primarily to obtain seed from controoled pollinations.
Breeding zone: A geographic area from which selections are made and interbred.

C

Character, Characteristic (Trait): The measurable or describable expression of a gene or group of genes, e.g. tree height, stem and branch form.
Cline (adj. Clinal): A character gradient. A gradual and essentially continuous change of character in a series of contiguous populations, frequently, but not always, associeted with gradual changes in an environment over distance.
Clonal forestry: Forest management practices that capitalize on the advantages provided by clones.
Clonal test: Evaluation of a genotype based upon its replicated performance.
Clone: A group of genetically identical organisms derived asexually.
Compatibility: The ability to form a successful union between scion and rootstock or the ability of two individuals, when crossed, to producea viable seed.
Controlled pollination: Application of pollen from a known source onto a selected receptive female flower, all other pollens being excluded.
Cross-pollination: Transfer of pollen from one parent to a receptive female flower of another.
Cutting: A detached portion of a plant which treated, may form roots and a new, complete plant.

D

Diallel cross: A mating design that results from crossing all parents in all combinations, including selfs and reciprocal crosses.
Dioecious: Having flowers of only one sex on a tree.
Donor: A selected individual used to supply material for vegetative propagation.

E

Ecotype: A group of individuals within a species adapted to a particular environment.
Environment: All external conditions under which an individual's genes act to determine that individual's final appearance. Examples of environmental factors are climate, soil, moisture, stand composition and spacing.
Environment variation: Variation in the apperance or performance of individuals resuling from their having been grown under different conditions (environment).
Exotic: A species introduced to an aren outside its natural range.

F

Family: A group of related individuals. More narrowly, a group of siblings.
Family test: Evaluation of individuals based upon the performance of their relatives.
Flower induction: Stimulation of the onset of flowering or the increasing of the number of flowers.
Forest Genetic Resource Management: The incorporation of genetic principles into forest practices in order to conserve genetic diversity in trees while promoting economic development through the maintenance and enhancement of productivity.
Foret tree breeding: Application of the knowledge of genetics in order to develop genetically improved trees.
Forest tee improvement: Application of tree breeding and of silvicultural practices in order to produce improved trees.
Full-sibs: Two or more siblings with both parents in common.

G

Gene: The unit of genetic material that is converted to a biochemical product in the cell.
Gene pool: All the genes in a population. More specifically, the genetic basis for the population's continued evolution.
General combining ability: The average performance of offspring of an individual when that individual is crossed with a random sample of some designated population.
Genetic gain: The difference in the performance of offspring derived from selected parents and the average performance of the original, unselected parental population.
Genetic variation: Vairation resulting from differences in genetic structure (genotype) of individuals.

H

Half-sibs: Two or more siblings with only one parents in common.
Hedge orchard: Cutting donors pruned low to retard maturation.
Heredity: The passing of genes from parent to offspring, which causes the offspring to resemble the parents.
Hybrid: The offspring of two genetically different parents.

I

Imperfect: Flowers with only one kind of reproductive organs, i.e. male or female parts but not both in the same flower.
Inbreeding: Producing offspring from the mating of relative.
Inbreeding depression: The loss ("depression") of vigour or fertility among the offspring of related individuals.
Incompatibility: Inability of scion and rootstock (q.v.) to unite successfully; or the inability of two individuals, when crossed, to produce a viable seed.
Interspecific hybridization: The crossing of individuals from different species.
Intraspecific hybridization: The crossing of genetically dissimilar individuals of the same species.
Isolation: The separation of a population from other populations. Isolation prevents or limits gene exchange.
Isozyme (Isoenzyme, Allozyme) studies: Method for looking at primary gene products (i.e. proteins) as observable single-gene markers.

J

Juvenility: A physiological state in which an individual exhibits characteristics different from those of the mature state, e.g. no flower production, leaf retention of hardwoods through winter, ease of rooting.

K

L

Local seed source: Source native to the locality in which the seedlings are to be grown.

M

Mating design: The planned pattern of controlled matings in some population(s) being bred.
Maturation: A physiological state in which an individual exhibits characteristics different from those of a young tree, e.g. production of reproductiver parts, reduction in growth rate, mortality of some limbs.
Monoecious: Having both male and female flowers on the same tree but borne in different places.

N

O

Offspring
: One or more first-generation decendants of an individual; progeny.
Outcrossing: The mating of unrelated individuals.

P

Partial-diallel cross: A diallel mating design in which some crosses, often selfs and/or reciprocals, are omitted. (See diallel cross.)
Pedigree: A record of the ancestry of an individual.
Perfect: Flowers with both male and female reproductive organs in the same flower.
Periodicity: An average number of years between major seed crops.
Persistent cone habit: The tendency of cones to remain on the tree after the cone is mature.
Phenology: The study of relationships between plant development and seasonal climate changes.
Planting zone: An area where planting stock from a given source can be planted.
Pollination: Deposition of pollen grains onto receptive parts of female flowers.
Population: A defined group of individuals.
Precocious flower habit: The characteristic of producing flowers at a very early age.
Production orchard: A plantation of selected seedlings or clones established primarily for seed production.
Progeny test: An evalutation of parents based upon the performance of their offspring.
Propagule: A reproduced organism that becomes an independent entity.
Provenance: The original geographic source of seed, pollen or propagules.

Q

R

Ramet: A genetically identical plant derived asexually from one individual (the ortet).
Recombination: The process by which new combinations of genes, not present in the parental population, are obtained in the offspring.
Roguing: Systematic removal of undesirable individuals from a stand of trees or an orchard.
Rootstock: A plant onto which a scion is grafted.

S

Scion: A plant part, normally a branchlet, that is grafted onto another plant.
Seed orchard (production orchard): A plantation consisting of seedlings or clones established from selected trees, primarily for the production of seed of proven genetic quality.
Seed zone: An area delimited by geographic bounds, climate and growing conditions within which seeds may be moved freely without undue risk.
Seed-collection area: A relatively large, pure, uniform stand of mature or semi-mature trees and average of above-average form and vigour that is selected for the collection of source-identified seed from felled trees.
Seed-production area: A relatively small area that is medium-aged, sexually mature, and above average in form and vigour that is upgraded through roguing and management for the production and collection of source-identified seeds from standing trees.
Selection: The choosing of individuals or populations for particular characteristics.
Selective breeding: Controlled pollination amongst a group of trees selected for one or more desirable characteristics.
Selfing: Crossing with self, self-fertilization.
Serotinous cone habit: The seeds remain within a closed cone after the seeds mature.
Site region: AN area delimited by geographic bounds and climate as described by G. A. Hills, "The classification and evaluation of site for forestry" (Ont. Dep. Lands and Forests, Div. Res., Res. Rep. 24, 1952; 41 pp.)
Stool bed: Hedge orchard, very low, usually applied to hardwoods.
Sub-line: Selections of superior trees that are divided into breeding groups. The breeding is done within, but not between, the groups to continue the sub-lines.
Superior tree (plus tree): A treet that appears phenotypically superior to the average.

T

Trait: A measurable expression of a gene or group of genes, e.g. height, stem form. (See Character.)
Tree breeding: See Forest treet breeding.
Tree Improvement: Breeding trees to select for desired characteristics, e.g. choosing parent trees that are taller, straighter, or more disease resistant than average.

U

V

Vascular plants: Plants that have specialized tissue for conducting fluids (sap), as opposed to the nonvascular plants such as mosses.
Vegetative propagation: The reproduction of genetically identical plants in a non-sexual manner, e.g. rooting of cutting.
Vegetative propagule: A reproduced organism derived from a parent donor in an asexual manner.
Viability: The potential of pollen or seed to germinate.